Rotary compressors



May 31, 1960 F. LUCK ROTARY coMPREssoRs 4 Sheets-Sheet 1 Filed Oct. 25, 1955 [lll 4 Sheets-Sheet 2 Filed Oct. 25, 1955 f. s W nl M wk Mm r2 A EM May 31, 1960 F. LUCK 2,938,663

Fi 1 e d 0 C t 2 5 l 9 55 Y Btl @half/ak A-TTGHLN ESS F. LCK

May 31, 1960 nited States ROTARY COMPRESSORS Friedrich Lck, Berlin-Tegel, Germany, assignor to Borsig Aktiengesellschaft, Berlin-Tegel, Germany, and Felix Wankel, Lindau, Germany Filed Oct. 25, 1955, Ser. No. 542,574

Claims priority, application Germany ct. 29, 1954 4 Claims. (Cl. 230-138) to regulate the transmitted amount of gas without steps,

it is necessary to use a movable steering device which holds the inlet channel open during the compression stroke for a shorter or longer time period.

In the event an excessive amount of gas has been sucked in this excess is transmitted during this time back into the suction conduit, with the result that the counterpressure in the cylinder isreached at a later time period. If the outflow edge were to remain unchanged at the same location then gas would ow hackv from the pressure conduit into the cylinder and would have to be'withdrawn for a second time. In case of a substantial gas ow this would result in substantial losses in energy and excessive knocking. Therefore it was found necessary to provide for a shifting of the steering edge for the outow.

It is apparent from each compressor diagram that the required distances for such adjustment are quite different for inilow and outflow steering edges. Therefore, it is not easily possible to regulate a rotory compressor at the inflow and outflow sides by means of a common steering slide.

An object of the present invention is to eliminate the above drawbacks of prior art constructions and to provide better regulation.

Another object is to provide a separate device by means of which the inlet and the outlet of a rotary compressor can be effectively regulated by a special construction.

In accomplishing the objects of the present invention it was found desirable to provide a single steering device for adjusting the steering edges controlling the inlet and the outlet openings provided in the rotor of the compressor on the one hand and on the other hand in the casing or the immovable hollow axis thereof. According to the invention two rotors located one Within the other are pro` vided, and the inflow and outilow take place by means of openings which are provided in one of the rotors and also in the casing or the immovable hollow axis.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings showing, by way of example, preferred embodiments of the inventive idea.

In the drawings:

Figure 1 is a diagrammatic section through a compressor constructed in accordance with the principles of the present invention.

Figure 2 is a compressor diagram.

Figure 3 is a diagrammatic section through a somewhat different compressor.

latent Figure 4 is another compressor diagram.

Figure 5 is a diagrammatic section through yet another compressor.

Figures 6 and 7 are working diagrams thereof.

Figure 8 is a section through still another compressor, and Figures 9 and 10 are working diagrams thereof.

The compressor shown in Figure 1 has rotors 1 and 2 which rotate about different axesin the same direction but with different speeds. The two rotors 1 and 2 and the enclosing parts defining three separate cylindrical spaces,- namely, a suction chamber 3, a suction cham-ber 4 and a compression chamber 5. .In the illustrated position of the two rotors the suction chamber 3 has the largest obtainable suction volume. If at that time the chamber 3 is already closed with respect to the suction tube 6, then as the rotors continue theirmovement gas will be compressed in the chamber 3 and finally will ilow into the pressure tube 7.

The casing of the machine includes an immovable piece 8 of curved form which has a lower edge 10 steering the inflow of the gas. The machine is also provided with a steering slide 9 having a right-hand edge 11 (looking in the direction of Figure 1), which steers the outflow of the gas.

The slide 9 may be shifted clockwise in the direction of the arrow illustrated in Figure l until its edge 11 assumes the position shown by broken lines. At that time the opposite edge 12 of the slide 9 will form with the member 8 a slot connecting the suction chamber 3 with the suction pipe 6.

When the rotors are further rotating the chamber 3 will continue to become smaller and a part of the sucked in gas will flow again into the suction space 6; this will continue until the steering edge 13 of the rotor 2 has passed the edge 12 of the slide 9. Thereafter the gas remaining in the chamber 3 will be compressed and removed. Due to the movement of the slide 9 its steering edge 11 has moved beyond the position shown in full lines in Figure l so that the gas is removed at a later time period.

The operation of the compressor constructed in accordance with the principles of the present invention is indicated upon the compressor diagram shown in Figure 2 illustrating relative changes in volume as a function of relative changes in pressure. On that diagram the line 14 represents the diminution of the suction volume when after a slight movement of the slide 9 there is a narrow slit between the member 8 and the slide 9, and whereby during further turning of the rotor gas ows through this slit from the suction chamber 3 to the suction tube 6. Then the edge 12 of the slide 9 takes over the functions of the edge 10 of the member 8. When the slide 9 is moved further, the edge 12 will separate the suction chamber 3 from the suction tube 6 at a later time period and then an amount of gas corresponding to the line 15 can ow additionally back to the suction tube 6. Thus, the total amount of gas returned to the suction conduit is equal to the sum of the distances 14 and 15. The distance 16 represents the change in the beginning of the outow caused by the fact that due to the angular shifting of the slide 9, the edge 11 which causes the beginning of the outflow is moved to the same angular etxent as the edge 12.

Since the changes in the volume of the cylindrical chambers do not take place linearly depending upon angular movements, the lengths 15 and 16 are not equal to each other. Since the relationship is a sine function, as in the case of every crank drive, Without the member 8 the line 16 would be many times longer than the line 15; however the line 16 must be considerably shorter in view of the amount to be compressed. The correct ratio is provided in this case by -the member 8, i.e. the addition fin :3,

opening' ofv 'the outlet'does not have to lie precisely'at' the end of the compressionline. In the case of quickly rotating compressors-this point may be so arrangedY that .aty the time Vcoiiterpress llfre is reached Vtlieo'utl s al- "readyipartly open.' Therefore the length"oftheY niber 8 will be made ,so thatthe outlet steering pointfoiffll possible partial loads -will "always lie at` asuitablejbut not yalways exactly the Ysaine distance 'in' frontl'of the end fof thecompressionlinen. l l y Y *Figure shows another possibilitynofproperly adjusting in relationrto each other the edge providing further end of the incu 'and-.the edge Providing this endpf ,the -outow it illusgates a compressor which, in viewef the v.above stated considerations, has` a slideV 17v provided with a swingable steeripgmmber '18which is connected with thegslidel? bya pivot extending parallel-to the axis of thecQmpreSsQr-- Y The membi r 1 8fmayi;be made 0f elastic material.l the C'urseggfmovsmentpf theslid 17 the member 18 may be guided by a rail 19 or the like, so that it will be raised at any d esi1' e d time,` and so that the extent to which it is raised'will; always increase with the increasing ;pathof 'movement of the slide 17, The guide rail 19 is connected tothe casingofithe compressor in any suitable manner (not shown)g. fConseque ntly, the operative o ut How-regulating edge will be constituted not by the rightfetur'rig ammini' or gas is indicated by the line 15a.

:handend of thefmember-IS but by the left-hand'end Y `(looking in the direction of Figur`e-3 The steering eect resulting from this' change iis shown ein the. compressor diagram of Figure 4. In this diagram the length 20, representsthej change in volume of the cylindrical suction chamber which corresponds to the would open thenY soilate'that super-pressure would exist in the cylinder. chamber and consequently a substantial amount of energy would be lost. The swingable member 18 when vraised moves the point of opening of the out- `iiow back tothe extent Vof stretch 22, so that excessive pressure is avoided.

' VTo avoid baflling losses theV regulation by means of the' swingable member V18 Vis"usable"only for' small regulatingranges, -orfinjcombination.with a regulation ofthe VV:sucked inlmassesby again removing Vthe g'as through the use of the .immovable piece 8 shown inFigu're l. Inthat case itis'possible` to extend the'regulation'range tothe v smallest partiallo'ads; Y t

lnorder to'fpi'vide for even smaller partial' loads, and in order to relieve the slidefrom one-sided tangential pressure upon the edgefdirected Vtoward the pressure conduit, the present invention provides a construction wherein a cylindrically curved steering slide which is circumferentially reciprocated between rotary and immovable parts of the compressor is additionally provided with a steering edge used for the closing of the gas Vremoving step. v

yAccording to a further VdevelopmentV of this invention it is also possible to eliminate that part of the slide which provides for -therendjof the Vinow and the beginning of the outdowprocedure; whereby the regulation takes place :only Vby those edges of the slide which providesfor the Yterminationof the outow and the beginningrofrthe itlowr intake-. f Y t v flurthernioeg' inacerdance with'the present inven- 'lllL a nflo'adcliannel' is'lpr'ovicled in thecaSDg. aud-is with'V Athe',intake conduit t, or with atmospheric i 1'.*I lfhsnels Qpnsd by that Y@des of the fslide which lproduces the closing of the outflowwhen the slide is adjusted to a position corresponding to that 'of the Regulating devices fof this Vtype and'thiropera'ting which `depends essentially: upon A L! diagrams are illustrated diagrammatically in two embodimerits inFigures' '5' to 10 ofthe drawings.

The rotary compressor shown in Figure 5 has two `rotors 1a and 2a which rotate about different axes and with different speeds but in the same direction. VThese two rotors form three separate operating chambers 3a, 4a and 5a. In the-position shown Yin Figure 5 the chamber 3a is ir1creasin'g`-in1 'sizeand'iF'scksn the gas from .jtheyintakez conduit 6a. Thecharnb'er 4ajcompressesthe rgasffwhich-is located thereinwh'ile thefchmbertaf after the outow of the gas into"Y the pressure conduit 7a has attained its smallest volume, The rotors are partly enclosed by'animmovableglating"irienbf 8a, having a frontedge 10a which 'causesthe vend of "the intakei in the illustrated full-load regulating position. A slide 9a has operative edges"v 11d and"12tardalsoan additional edge 13. When the slide 9 is rotated the edge 12a takes over the 4regulation instead of the vedge 10al in suchY manner thatf'a art of the'sucked in'gas canowbackto the intakelc'onduit A6a. VIn the'fdiagram4 shown in Figure 6 the YThefb'girining of the outflow isildetprmined bytheedge w11a. The" ,furtherthe slide9ais nijovedin the" direction of"rotati`on of the:ioiripressorfthe'latei'- Will'begin the :outflow as is apparent from the line 16a ofr'thediagram `lsliownin'Figure 6. y I t u -'lhe-Uadditi'onal operating'ed'ge 113 produces the end of tlieoutotm In the illustrated full-'load position `the edge Vconduit'la. lfnthe slide 9d is.V shifted in the direction of rotation nof the compressor', the edgel'l will move V'further downwardly (looking inthe 'direction' ofFigure v5);' then "the chaises? 5@ Whdibsiess @geen 'ig Size remains connected with thepressure conduit 7 a andcan be filled with compressedfgas until'tlie edge'l'la ofthenrotor 2a slidesy past the edge 1.13. This procedure oiiilling the operating space withlthe Vgas' isf-indicated by the line 17 in the diagram or" Figure 6, The gas located in the chamber' Sd and Yin the clearance space will now expandlwhile giv- 'inf' upfpower, to theV volume `indicatedlby the length 18 Figure 6. Thellength 19 represents the amount of gas actually'ksucked lin and transrrlitted. by the. compresson LThe ladditional steering edge 113Amakeslit possible to 'cause 4return flow of apart of the gas from" the compression conduit Yto Vthe intake conduit, and this makes it possible *to provide for sinall partialloads.` Furthermore, sincev pressuret prevailinggin the compression conduit is `exerted upon the-steering edge 11a, as Well as the steering edge 113, the slidev 9a willbe tangentially discharged of load. Y Y

The machine includes a no-loadmchannel 120 which Vis connected with the intake channel 6 or with atmospheric airfandwhich is opened by thejsteering edge'113 of the slide 9a, which; causes the-end of the outow procedure. Due to the provision of the`noload channel-129, and when the slide 9a isset to a position corresponding to the smallest partial load, it is'possible toincreasethe regula tion ofthe'partial load` range to a no-load regulation.

' If now the slide 9a is further shifted in the direction of therotation, beyond the positionsho'wn by broken lines lin jFigure 5," then the channel'will be opened by the edgeV 113so that adirectvconriectionvis provided bythe suction or intake.' conduitY close to the'ifinlet' fopening into the machine. This valve is closed when'theYslide'reaches tirano-loadposition.A "By-means of'fthis lvalve the machine energy. u

Figure 7 illustratesa'fnoladfdiagranif,the-*size of ling cond Valling in the compression chair'ib'en' i -the illustrated position of the slide.

E well as in the ones earlier described, the change in volume is illusrtated as a function of the change in pressure. The line designated at 1 ata represents the line of atmospheric pressure. When the slide 9a is in the no-load position and the regulating valve in the suction tube is closed, the operating pressure of the machine is below the atmospheric line, as indicated in Fig. 7. The length 121 corresponds to the amount of gas which must be compressed continuously at a substantially reduced intake pressure, and which results from lack of complete sealing. The point 122 upon the compression curve characterizes the steering position reached by the edge 11a and the length 123 corresponds to the amount of gas flowing back from the compression conduit 7a into the 'working chamber a until the chamber is cut off by the steering edge 113. Then the amount of gas enclosed in the working chamber 5a can expand while giving up power until the steering edge 24 establishes the connection between the chamber 5a and the intake conduit 6a.

The additional regulation of the transmitted amount of gas by the steering edge 113 can be increased to such an extent that regulation by steering edge 12a becomes superuous. Then the construction of the regulating device is considerably simplified.

Figure 8 illustrates a construction wherein the movable slide 25 has two steering edges 26 and 27. The edge 26 terminates the gas outow while the edge 27 regulates the beginning of the take-in. The edge 28 which determines the beginning of the outflow is formed by the immovable casing.

Figure 9 illustrates a full-load diagram which occurs in If the slide 2S is shifted downwardly into the position shown by broken lines in Figure 8, gas can flow back from the compression conduit into the working space which begins to increasel again. This procedure is indicated in the diagram of Figure 9 by the line 29. When the Working space is closed off by the edge 26 the gas expands giving up power until the steering edge 27 provides for a connection to the intake conduit. Line 36 remaining upon the intake line of the diagram shown in Figure 9, indicates the actual sucked-in partial load amount.

This regulating device can be also amplified through the addition of a no-load device. Figure 8 shows a channel 31 which again provides for a connection between the compression conduit and the atmospheric air or the intake conduit.

A valve (not shown) is used to close the intake or suction conduit by hand or automatically. When the valve is closed a no-load diagram is produced which may have the form shown in Figure l0.

It is apparent that various changes may be made in the described regulating devices. rI'hese devices, particularly the device shown in Figure 8, may be used for the regulating of admission in expansion machines. All such and other variations and modifications are to be included within the scope of the present invention.

What is claimed is:

l. In a rotary compressor, a stationary casing having substantially opposedfconcentric inner surfaces forming cylindrical sections, said casing 4having formed therein inlet and outlet openings between said surfaces, an outer hollow rotor located between said surfaces and between said inlet and outlet openings and having outer cylindrical surfaces which are concentrical with said inner surfaces of the casing, an inner rotor eccentrically mounted within said outer rotor-and having curved outer surfaces, said outer rotor having inwardly projecting portions engaging said outer surfaces of the inner rotor and slidable relatively thereto when said rotors are rotated in the same direction at different speeds, said outer surfaces of the inner rotor and said inwardly projecting portions of the outer rotor enclosing a plurality of working chambers which expand and contract when said rotors are rotated at different speeds, said outer surfaces of the inner rotor and said inwardly projecting portions of the outer Irotor being so shaped thatsaid chambers expand as they move past said inlet opening and contract as they move toward and past said outlet opening, said outer rotor having openings communicating with said chambers and adapted to communicate with said inlet and outlet openings during the rotation of said outer rotor, a circumferentially movable steering slide having concentrical outer and inner surfaces concentrical -with and engaging one of said inner surfaces of the casing and the outer surfaces of said outerrotor, respectively, said slide being located on the side wherein said chambers attain their largest expansion volume and having two opposed edges, one of said edges being located adjacent said inlet opening for determining the end of the suction period of said working chambers, the other one of said edges being located adjacent said outlet opening for determining the beginning of the outflow period of said working chambers', and an immovable member having concentrical outer and inner surfaces constituting continuations of said inner surfaces of the casing and the outer surfaces of said outer rotor,respectively, said immovable member having an edge located adjacent said one edge of said slide andan opposite edge, the two edges of said member being located in said inlet opening, said one edge of said immovable member being adapted to be engaged by said one edge of said slide, whereby the flow from a working chamber to the inlet opening may be varied.

2. In a rotary compressor, a stationary casing having substantially opposed concentric inner surfaces forming cylindrical sections, said casing having formed therein inlet and outlet openings between said surfaces, an outer hollow rotor located between said surfaces and between said inlet and outlet openings and having outer cylindrical surfaces which are concentrical with said inner surfaces of the casing, an inner rotor eccentrically mounted within said outer rotor and having curved outer surfaces, said outer rotor having inwardly projecting portions engaging said outer surfaces of the inner rotor and slidable relatively thereto when said rotors are rotated in the same direction at different speeds, said outer surfaces of the inner rotor and said inwardly projecting portions of the outer rotor enclosing a plurality ofworking chambers which expand and contract when said rotors are rot-ated at different speeds, said outer surfaces of the inner rotor and said inwardly projecting portions of the outer rotor being so shaped that said chambers expand as they move past said inlet opening and contract as they move toward and past said outlet opening, said outer rotor having openings communicating with said chambers and `adapted to communicate with said inlet and outlet openings during the rotation of said outer rotor, a circumferentially movable steering slide having concentrical outer and inner surfaces concentrical with and engaging one of said inner surfaces of the casing and the outer surface of said outer rotor, respectively, said slide being located on the side wherein said ch-ambers attain their largest expansion volume and having two opposed edges, one of said edges being located adjacent said inlet opening for determining the end of the suction period of said working chambers, the other one of said edges being located adjacent said outlet opening, a curved steering member connected to said other edge of said slide for swinging movement about an axis parallel to the axis of rotation of said outer rotor, said steering member having an outer edge located in said outow opening for determining the beginning of the outow period of said working chambers, and a guide rail connected to said casing and located in the path of -movement of said steering member, said guide rail being substantially narrower than said outow opening in a plane perpendicular to the outtlow of the fluid through the outow opening and being adapted to be engaged by said steering member and raising said steering member relatively to said slide `when said slide is moved in the direction of rotation-of 'said' outer foton t Y,

le3. A: rotaryffcompressor, -a stationary Vcasingi'having substantially opposedV concentric-inner surfaces forming cylindrical'sections,=sad casing'havingi formedtherein inletv and outlet openings between fsaid surfaces, an outer hollowr'otor locatedfbetween 'said'A surfaces and between said inletfand` outleteopeningsfand having outer: cylindrical surfaces which are 'concentrical --witlrsaid-ginner"suri` faces L of the' casing, anfinner rotor -e'ccentrically mounted .within saidouter' rotor and having Vcurved outer surfaces, Ysaidouterrotr; having inwardly "projecting portions en- :gaging vsaidoutergsurfaces ofthe inner rotrrand-slidable `relatively thereto when Asaid` Arotors are rotated in the same Vdirection a-tfdileren't speeds; said outerrsurfaces of :ftheinner n-rotor and: said rinwardly kprojecting portions of the outer'rtor'enclosing` a pluralitygof-working f chambers whi'chiexpand; and 'co'ntractfwhen said rotors are rotated' :indifferent speeds,V said outerf'surfacesiof the inner rotorand said inwardly projecting-portions of theouter rotor being'so shaped that saidchambersv expandv as they move pastsaid'inlet` opening and contract' as they 'move toward and past saidfoutlet `opening'g-said Youtenroto'r jhaving openings communicating Vwith said chambersV and f adapted to communicate withy 'said inlet' and 4outlet open rings duringY the rotationl of said outer rotor, a 'circumferentially movable steering slide `having concentrical outer and'inner'surfaces Vcocentr'ical with-and engaging vone of saidinner surfaces off thecasingand `the outer surfaces of said outerV rotor, respectively, said`slide being 'located On'the'sidewherein said chambers attain their largestlexpansion -volume. andhaving two opposedV edges, Vone of said edgeslbeing located adjacentsaid inlet opening for determining the-end of thexrsuction period offs'aid working chambers, the other one of said'edges being lo Acated adjacent-said outlet opening for determining the Ybeginning of the outiiow period of said working chambers, :an additional slide member movable with said slide and constituting a Acontinuation thereof, said additional vslide member having concentrical outer and inner surfaces concentrical with and engaging theV other one of said inner surfaces of thel casing and' the outer surfaces of said outer rotor, respectively, said additional slide member being located on the side wherein said chambers attain their smallest contraction volume and having two :opposed edges, one of the last-mentioned .edges being located adjacent said outlet opening for determining'the vend of the outflow period of -said working chambers, the :other one of the last-mentioned edges'being located adjacent said inlet opening for determining the beginning of the suction period of said working chambers, and an immovable member having concentrical outer and inner surfaces constituting continuations of said inner surfaces of the casing and the outer surfaces of said outer rotor,

respectively, Vsaid immovable member having an edge located adjacent said' one Vedge of said slide and an opposite edge, the two edges of said member being located in Said inlet opening, said one edge of said immovable member being adapted to be engaged by said one edge vof said slide, whereby the beginning of the compression period of said working chambers is determined selectivelyd'epending upon the position of said slide by said opn posite edge of the immovable member or by vsaid one edge of said slide, Vsaid casing having a no-load channel formed therein and communicating with said other one of theV inner surfaces of said casing on the rside wherein esaidworking chambers attain their-smallest contraction '8 volumeandfa point of low pressure, said. no-loadfcham 'nel' beingsopenedzrby Y.said-y slide atA -no,load;andfibein'g closed by said'slide during 'loadoperations 4. Inla rotary'tcoinpressor,::aistationaryicasing having t substantiallylopposed concentric inner' isurfaces-forming cylindrical'Y sections', '.said casing Ahaving-:formed 4 therein inlet vand. butl'e't openings betweensaidfsurfaces," .anfouter hollow rotor` located between zsaidlsurfaces arid :between :sid yinlet: andi outlet openings r and having "outer cylindrical 1 surfaces 'which' are? concentrical VwithV 'said'inner surfaces. of the casing,'annnerrotoreccentrically mounted within' said outer-rotor andfhavingcurved outer surfaces; s'aid outer rotor Vhaving inwardly `projecting portions engaging 'sa'id outer surfaces of theinner rotor and slidarble relativelyfthereto'when' saidrotors -are rotated in'the Asame'idirectirnr-atvndifferent vspeedsgusaid outer surfaces of the inner rotorand 'said inwardlyprojecting portions of the outer. rotorenclosing.af'plurality of working chambers which expand vLand!` contract whenv said rotors i are rotated at Vdifferentspeeds,fsaidouter surfaces ofiA the inner .rotor and' said. inwardly projecting portions: of the outerirotorlbeirlg solshapedthat said Ychambers expand as theymove past Isaid inlet-opening and contractlfas they move toward and past said outlet opening, said outer i rotorfhavingropenngs'communicating with said chambers andadapted to communicate'with'fsaidv inlet and outlet openings duringthe-irotation of..-said. outer rotor,` said ."casing having.'.anfedgedeningrone end'of: said outflow fopening,lwherebylthe sliding of `said outer rotor-,relatively to said edge determines the beginning of thezoutflow period of said working chamberspandta slide'vmemfberhavingl- 'concentrical outer* and inner.k surfaces concentrical'with" and Vengaging one of saidfinner surfaces of the casing 'and lthe outer surfaces of said outer rotor, said slide' member being located on the sidewherein said chambers attain theirV smallest contractionivolumefand 'having two ',opposededges, one ofthe last-mentioned edges 'being located adjacent 'said outlet openingfefor determiningthe end of the 'outflow period of-said working chambers, fthe other one ofthe last-mentioned edges being located adjacent said inlet opening for determining the beginning of the suction period of said workingtchambers,`said casing'having a no-load channel yformed therein and communicating -with said one inner surface of said casing on the sidey wherein said'workingv chambersfattain-their smallest contraction volumetand a point of--low pressure, said no-load channel being opened byz'saidV slide at noload-and-beingvclosed by said slide during load operations. v

References Cited in the'le of 'thispatent UNITEDl STATES PA'ITPTS Re. 23,086 VHoll l Feb..-22,:1949 1,482,807 Newber'f-- Feb. 5, 1,924 2,011,338 Hill Aug. 13, 1935 2,371,922 Saito Mar. 20, 1945 2,426,491 Dillon Aug. 26,11947 2,509,321 Topanelian May 30, 1950 2,630,759 MahlonY Mar. 10, 1953 2,658,344 f \Ve1ch Nov.Y 1.0', 1.953

v FOREIGN PATENTS 130,602 Australia Dee. 1o, V1948 152,671 Switzerland Nov. 17,1930 160,003 A Switzerland Apr. 17,' 1933 394,985 l Great Britain July 5,k 1933 

